Japanese Patent Laying-Open No. 8-126121, Japanese Patent Laying-Open No. 2002-171606, Japanese Patent Laying-Open No. 2000-324857, Japanese Patent Laying-Open No. 10-117403, Japanese Patent Laying-Open No. 10-225014, and Japanese Patent Laying-Open No. 4-295202 disclose on-board charging apparatuses. For example, the on-board charging apparatus disclosed in Japanese Patent Laying-Open No. 8-126121 includes three-phase coils CA, CB, inverters IA, IB, and a battery. A commercial power source is connected between a neutral point of three-phase coil CA and a neutral point of three-phase coil CB.
Inverters IA and IB are provided corresponding to three-phase coils CA and CB, respectively, and connected to three-phase coils CA and CB, respectively. Inverters IA and IB are connected in parallel to the battery.
When charging the battery, inverter IA is controlled to allow an equal current to pass through each of the three coils of three-phase coil CA, while inverter IB is controlled to allow a current, which is equal to that passing through the three coils of three-phase coil CA, to pass through each of the three coils of three-phase coil CB. Thus, inverters IA and IB converts an AC voltage from the commercial power source to a DC voltage, and supplies the battery.
However, Japanese Patent Laying-Open No. 8-126121 discloses only the configuration for charging a battery using a commercial power source, and therefore an AC voltage as a commercial power source can hardly be generated using two three-phase coils.